This community in Bonjol, West Sumatra, use hydropower to extract pieces of gold from stones.

The stones are placed into a rotating drum that grinds them down in an eight-hour-long process.

However, the process pollutes the nearby rivers as mercury flows back into the water.

These stones are not ordinary stones. Most likely contains gold. It is not easy to get gold from this stone. Initially the stone had to be crushed. then the stone is inserted into Galondong. The rotating drum that grinds the crushed stone. This process lasts eight hours. Into this galondong, mercury and water are also added. Mercury is the one who will catch the gold in the galondong. eight drums yield 3 grams of gold, if lucky.
the problem is that the water and the processed stone are all contaminated with mercury. all the water and sediment flows into the river. In the end, all river water and living creatures in the river are polluted. The people of Bonjol are starting to worry about the quality of their river.
part of the community in the Bonjol area, Pasaman. West Sumatra has always been a gold miner. since last 20 years they started using mercury. Not everyone here likes this. rice farmers, fish farmers do not like this. it could be that in the future there will be many conflicts and health problems.
actually this health problem has been felt by the miners and their families ... but they ignore it.
another problem is the noise from the Galondong spinning diesel engine. some miners move their gallons with hydropower